Grate



March 15, 1938.

l. C. SMITH GRATE 2 Sheets-Sheet 1 Filed April 20, 1937 m 0 Z W w M wMarch 15 1938. SMTH 2,111,438

GRATE Fild April 20, 1937 2 Sheets-Sheet 2 Patented Mar. 15, 1938 Ira C.Smith, Scranton, Pa. Application April 20, 1937, Serial No. 138,045

6 Claims.

This invention relates to furnace grates generally; and particularly tooscillatory grates adapted'for use with automatic stoker mechanism.

The main object of the invention is to provide a mounting for a grate ofthe type disclosed in my United States application Serial No. 95,463,filed August 11, 1936, and allowed January 4, 1937; and in which thegrate is normally inclined "to the horizontal in such manner as toprovide 1 0. for the automatic feed and even distribution of coalfrom amagazine arranged at the upper end thereof.

A further object of the invention is to provide a grate of the characterdescribed with mechal5 nism for oscillating the grate as a Whole aboutits lower end, while at the same time rotating the bars of the grate tocut from the fire bed the ashes and debris which ordinarily interferewith the emcient operation of the furnace.

' Other objects of the invention will become apparent as the detaileddescription thereof pro- 7 i Figure 3 is a vertical section taken on theline 3-3 of Figure 2;

Figures 4, 5, 6, and 7 are longitudinal sections 7 of the grateillustrating the positions of the grate with respect to the magazineduring a complete oscillatory movement about its lower axis;

Figure 8 is a section taken on the line 8-8 of Figure 4; and

Figure 9 is a section on the line 9-9 of Figure 1.

1 3 Referring to the drawings, in which similar parts are designated bylike numerals:

The'refe'rence numeral 9 designatesa furnace provided with a fuelmagazine It, and a combustion furnace chamber H. The magazine H] isprovided with the bottom wall 12, inclined downwardly toward thecombustion chamber 5 i to feed fuel by gravity onto the grate designatedgenerally by the reference numeral 13.

The grate 13 comprises a frame having side i 50 bars 14 and I5 connectedat one end by a cross bar IS, and near their other ends by a cross barl'l. The side bars 14 and E5 project beyond the 1 cross bar 11; andtheir projecting ends have a shaft 18, journaled therein. One end of theshaft 5 48 projects through the side bar 14 to seat rotatably in aU-shaped bracket 19, suitably secured to the side wall 20 of the furnace9.

The other end of the shaft 18 projects through the side bar of the grateand through an aperture 2! formed in the side wall 22 of the furnace,J45 the aperture 2! forming a journal bearing for the shaft 18. A seriesof shafts 23 are journaled parallel to each other and to the shaft l8 inslots 24 formed in the side bars l4 and I5. One

end of each shaft 23 is reduced to form a shoule10 'der 25, seatingagainst the inside of the side bar M. The reduced end 26 fits within theslot 24, and is locked rotatably in the said slot 24 by means of alocking bar 21, provided with a series of slots 28, fitting over thereduced ends 26 of 51.15 the shafts 23. The rear end of the locking bar21 is apertured to fit the shaft I8, about which it may be rotated intoand out of locking position with respect to the reduced ends 26 of theshafts 23. When the locking bar 21 is in locking; position, it may besecured in such position by' means of the screws 29. 1

A locking bar 39 similar in every respect tothe locking bar 2'5 isrotatably mounted "on the other end of the shaft l8 and is adapted to besimilarly secured in looking rotation to the side bar [5 by means of thescrews 3|. The shafts'23 project through arcuate slots 32 formed in theside wall 22 to provide for a somewhat limited oscillation of the gratel3 as a whole about the axis of shaft IS. The free end of the grate issupported, by means of a pair of cams 33 fixed to the outer shaft 23 andresting upon brackets 34, suitably secured to the side walls 20 and 22of the furnace. 35

The parallel shafts 23 are each provided with" a series of spaced apartfire-supporting members 35, the members on one shaft being staggeredwith respect to those on the adjacent shaft or shafts. The shaft 58 hassecured thereto a pair of sprockets 35 and 31, and a crank handle 38.The sprockets 36 and 31 are operatively connected by means of sprocketchains 38' and 39 to sprockets fixed to the ends of the parallel shafts23; so as to rotate all of said shafts simul 5 taneously and in the samedirection. It will be obvious from inspection of the drawings and whenthe shaft 18 is rotated-by means of the crank 38 all the shafts 23 andtheme supporting members arranged thereon will be 5 simultaneouslyrotating to effect a cutting operation on the ashes or lower layer ofthe superposed fire bed. During the rotation of the shaft 23 the cams 33will also be rotated, and by contact with their supporting bracket 34will cause the free end of the grate l3 to swing toward and from thedownwardly inclined bottom wall l2 of the magazine In.

The cross bar It is provided with a series of lugs 40 adapted to receivetongues 4| which project downwardly from a cut-off bar 42 detachablymounted on the upper edge of the bar l6 and shaped to swing across andclose to the end of the bottom plate l2 of the magazine It]. Theoscillatory movements of the grate l3 about its pivot shaft I8, isillustrated in Figures 4, 5, 6, and 7 of the drawings. Figure 4 showsthe normal raised position of the grate I 3. When the shafts 23 arerotated anti-clockwise, as shown in the drawings, the grate drops fromthe normal position shown in Figure 4 to the lowered position shown inFigure 5. This preliminary movement serves to break the crust formed bythe fire bed. Continued anti-clockwise rotation of the shafts 23 movesthe grate from the position shown in Figure to that shown in Figure 6 inwhich the scoop-like fingers of the fire supporting members 35 are invertical position.

It will be noted that the upper end of the cutoff bar 42 projects abovethe downwardly inclined bottom wall E2 of the magazine, when the grateis positioned as shown in Figure 6. The cams 33 are substantiallycircular between the radii 43 and 44 so that further anti-clockwiserotation of the cams through an angle of about 90, will produce verylittle movement of the grate section 35 with respect to the bottom plateE2 of the magazine. Further anti-clockwise movement from the positionshown in Figure 6, through that shown 'in Figure 7, to its normalposition shown in Figure 4, merely effects a slight rocking movementwhich facilitates the scooping action of the members 35 on the ashesconstituting the lower part of the fire bed.

It will be evident from inspection of Figures 4 to '7, inclusive, thatrotation of the pivot shaft l8 not only causes rotation of all theshafts 23, with their fire supporting members 35, but also causes adecided drop from the position shown in Figure 4 to that shown in Figure5, to cause a break in the superposed fire bed. This break, accompaniedby continued rotation of the fire supporting members 35 insures aneffective removal of the ashes from the fire bed, and a dropping thereofinto the ash pit.

The staggered relation of the fire-supporting members 35 on each shaftwith respect, to the positioning of these members on adjacent shaftsenhances the draft through the fire-bed, and increases the efiiciency ofash removal from the fire bed. The bar 42 at the upper end of the grateis also provided with apertures 45 which serve as draft apertures forthe fire bed and also as passageways for ashes which may be shaken fromthe fire bed by the oscillation of the grate as a whole.

Numerous variations may doubtless be devised by persons skilled in theart without departing from the principles of my invention. 1, therefore,desire no limitations to be imposed on my invention, except such as areindicated in the appended claims.

What I claim is:

1. A furnace comprising a casing partitioned to form a furnace chamberand a magazine for fuel, a grate comprising a substantially rectangularframe pivoted at one end of said chamber, a plurality of shaftsjournaled parallel to each other in said frame, fire supporting membersspaced apart along each of said shafts and arranged in staggeredrelation with respect to the fire supporting members on adjacent shafts,and cooperating means on said casing and grate for simultaneouslyrotating said shafts and for oscillating said grate to cause the freeend thereof to reciprocate with respect to said magazine.

2. A furnace comprising a casing partitioned to form a furnace chamberand a magazine for fuel, a grate comprising a substantially rectangularframe pivoted at one end of said chamber, a plurality of shaftsjournaled parallel to each other in said frame, fire supporting membersspaced apart along each of said shafts and arranged in staggeredrelation with respect to the fire supporting members on adjacent shafts,supports on the opposite side walls of said chamber for the free end ofsaid grate, cams secured to the shaft nearest said free end and restingupon said supports, and means on said casing and shafts forsimultaneously rotating said shafts and for oscillating the free end ofsaid grate with respect to said magazine.

3. A furnace comprising a casing partitioned to form a furnace chamberand a magazine for fuel,

a grate having a substantially rectangular frame pivoted at one end tothe opposite side Walls of said chamber, a plurality of shafts journaledparallel to each other in said frame, fire supporting members spacedapart along each of said shafts, means for supporting the free end ofsaid grate to maintain the grate normally inclined to the horizontal,said magazine having a bottom wall inclined to the horizontal andprojecting into said furnace chamber, and cooperating means on saidcasing and said shafts for simultaneously rotating said shafts and forcausing the free end of said grate to swing past the projecting end wallof said magazine.

4. A furnace comprising a casing partitioned to form a furnace chamberand a magazine for fuel, a grate having a substantially rectangularframe pivoted at one end to the opposite side walls of said chamber, aplurality of shafts journaled parallel to each other in said frame, firesupporting members spaced apart along each of said shafts, means forsupporting the free end of said grate to maintain the grate normallyinclined to the horizontal and projecting into said furnace chamber,said magazine having a bottom wall inclined to the horizontal andprojecting into said furnace chamber adjacent the free end of saidframe, a cutting section detachably connected to the free end of saidframe and adapted to swing with said frame with respect to theprojecting end of said bottom wall, and means connected to said casingand shafts for simultaneously rotating all of said shafts and foroscillating the free end of said frame to swing said cutting sectiontoward and from the projecting end of said bottom wall.

5. A furnace comprising a casing partitioned to form a furnace chamberand a magazine for fuel, a grate having a substantially rectangularframe pivoted at one of its ends in said chamber, said magazine having abottom wall inclined to the horizontal and projecting downwardly intosaid furnace chamber, a plurality of shafts journaled parallel to eachother in said frame and having fire supporting members spaced apartthereon, and cooperating means on said casing and shafts forsimultaneously rotating said shafts and for oscillating the grates sothat its free end swings past the downwardly projecting end of saidbottom wall.

6. A furnace comprising a casing partitioned to posite side walls ofsaid chamber, cams fixed to one of the shafts remote from the pivotedend, of said frame and resting upon said brackets, a cutting sectionprojecting upwardly from the free end of said frame and adapted to swingpast the inwardly projecting end of said bottom wall, and gearing forsimultaneously rotating said shafts and cams.

' IRA 0'. SMITH.

